One of the difficulties for orthodontists in working with buccal tubes is the difficulty of inserting an orthodontic archwire into the archwire passage or bore of the buccal tube. Because orthodontic archwires and archwire-receiving bores are quite small, and buccal tubes are positioned toward the back of the mouth, threading of the orthodontic wires into the bores can be quite challenging. Furthermore, if a tooth is severely maloccluded, such as for example a second bicuspid, it may not be possible to thread an orthodontic wire from a bracket on that tooth through a buccal tube on the adjacent first molar, in which case an orthodontist may have to choose a less desirable treatment option.
U.S. Pat. No. 3,874,080 has sought to address the problem of threading an archwire into a buccal tube by providing a buccal end tube device having two spaced substantially parallel tabs supported on a mounting portion. Each of the parallel tabs is provided with a plurality of apertures for receiving an orthodontic archwire, and the wire-receiving mesial ends of the apertures may be tapered with an internal conical or prismatic taper to facilitate location and entry of an archwire into the respective apertures. The buccal end tube device includes several apertures on each parallel tab so that an orthodontist may choose a set of apertures on the device to exert more or less tooth moving force.
One of the disadvantages of the '080 device is that the tapered wire-receiving ends of the apertures still are relatively small. In addition, once an orthodontist has threaded an archwire through an aperture in the mesial tab, the clinician still must thread the archwire through an aperture in the distal tab. However, because the archwire already has been threaded through the mesial tab, the orthodontist may take only very limited advantage of any taper in the mesial side of the distal tab. Furthermore, because the parallel tabs include a number of different apertures, the overall end tube device is quite large.
Another challenge for orthodontists in the use of buccal tubes is the insertion of auxiliary wires into auxiliary passages or bores. Furthermore, patients wearing extra-oral or intra-oral devices such as headgear or lip bumpers must position the distal ends of a device such as a face bow or lip bumper into an auxiliary passage or bore on the buccal tube appliances, and because of the small size and location of the appliances, proper engagement of an extra-oral or intra-oral device with a buccal tube can be quite difficult.
U.S. Pat. No. 4,963,092 has attempted to address the challenge of inserting an auxiliary wire into a buccal tube by providing a mesial, open-ended cylindrical passage and a distal rectangular passage aligned with the cylindrical passage. The cylindrical passage is larger in diameter than the rectangular passage, and a funnel-shaped wall connects the two passages in order to guide an end of a rectangular wire toward a position within the rectangular passage.
One of the limitations of the '092 appliance is that the funnel-shaped wall connecting the two passages is positioned approximately three-quarters of the way toward the distal end of the appliance. Therefore, an orthodontist is unable to take full advantage of the angle of the funnel-shaped wall when placing a wire into the rectangular passage. Furthermore, the funnel-shaped wall exists only on the inside of the passageway, while the outside diameter of the tube remains large along the entire length of the appliance, resulting in a buccal tube appliance which is not very compact.
U.S. Pat. Nos. 5,057,012 and 5,151,028 have dealt with the face bow-lip bumper issue by providing an internally flared or enlarged mesial opening to enhance insertion of a face bow or lip bumper by a patient. However, the outside diameter of the tube is relatively constant or only very slightly tapered, resulting in a buccal tube appliance with a relatively large overall size.
Therefore, it would be advantageous to have a buccal tube having a passage or bore with an enlarged mesial opening for easier insertion of an orthodontic archwire while maintaining a relatively small overall size to the buccal tube. It also would be desirable to provide an enlarged mesial opening on the auxiliary passage or bore of buccal tubes having an auxiliary passage, where the enlarged opening is achieved while maintaining a small overall size to the auxiliary tube.